| This magneto is the type of small generator incorporated
in early telephones, and was used to ring telephone bells at the central
office and on the subscriber's party line. It is difficult to date, but
I would guess that it was built in the1920s.
Turning the crank even slowly produces a rapid rotation rate for the geared-up armature, which lies between the poles of the permanent magnet.
In my early days of teaching I gave a nasty shock with this apparatus to a student who had grasped the wires from the commutator brushes.
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